The inventive concept relates generally to electronic memory technologies. More particularly, the inventive concept relates to nonvolatile memory devices and related methods of operation.
Semiconductor memory devices can be roughly divided into two categories according to whether they retain stored data when disconnected from power. These categories include volatile memory devices, which lose stored data when disconnected from power, and nonvolatile memory devices, which retain stored data when disconnected from power. Examples of volatile memory devices include dynamic random access memory (DRAM) and static random access memory (SRAM). Examples of nonvolatile memory include mask read only memory (MROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), and electrically erasable programmable read only memory (EEPROM).
Some nonvolatile memory devices are capable of storing more than one bit of data per memory cell. Such nonvolatile memory devices are commonly referred to as multi-bit nonvolatile memory devices or multi-level cell (MLC) nonvolatile memory devices. Nonvolatile memory devices that store more than one bit of data per memory cell may provide higher storage capacity than those that store only one bit of data per memory cell. However, they may suffer from slower operation and reduced reliability, among other things. Accordingly, researchers are engaged in ongoing efforts to improve these and other performance aspects of MLC nonvolatile memory devices.